| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 2,112 | 2,188 | 4,470 | |
| 2020 | D | 2,491 | 2,207 | 4,784 | |
| 2016 | D | 2,094 | 1,853 | 4,237 | |
| 2012 | D | 2,882 | 1,667 | 4,626 | |
| 2008 | D | 3,516 | 1,628 | 5,218 | |
| 2004 | D | 2,215 | 2,028 | 4,311 | |
| 2000 | D | 2,345 | 1,651 | 4,161 | |
| 1996 | D | 2,453 | 1,336 | 4,239 | |
| 1992 | D | 2,154 | 1,377 | 4,394 | |
| 1988 | D | 2,233 | 1,711 | 3,984 | |
| 1984 | D | 2,681 | 2,390 | 5,110 | |
| 1980 | R | 1,644 | 1,730 | 3,735 | |
| 1976 | D | 1,962 | 1,615 | 3,630 | |
| 1972 | R | 1,552 | 2,148 | 3,824 | |
| 1968 | R | 1,319 | 1,789 | 3,321 | |
| 1964 | D | 2,509 | 1,481 | 3,993 | |
| 1960 | R | 1,497 | 1,724 | 3,224 | |
| 1956 | R | 1,342 | 1,739 | 3,081 | |
| 1952 | R | 1,114 | 2,165 | 3,285 | |
| 1948 | R | 1,328 | 1,334 | 2,702 | |
| 1944 | R | 1,289 | 1,394 | 2,695 | |
| 1940 | D | 1,926 | 1,616 | 3,560 | |
| 1936 | D | 2,037 | 1,087 | 3,186 | |
| 1932 | D | 1,637 | 957 | 2,628 | |
| 1928 | R | 1,017 | 1,274 | 2,297 | |
| 1924 | R | 327 | 1,082 | 1,874 | |
| 1920 | R | 475 | 1,062 | 1,605 | |
| 1916 | D | 740 | 497 | 1,254 | |
| 1912 | — | — | — | — | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Big Horn County is home to the Crow Reservation, and Native American voters—roughly half the population—have historically driven Democratic margins that make this one of Montana's most competitive counties despite its rural ranching character.
The county's recent history is a story of close margins. The Democratic margin reached thirty-six points in 2008; the Republican margin reached forty points in 1924. Most other elections have been decided by single-digit points.
Big Horn County's demographics — a population of 12,891, a 30% non-Hispanic-white share, a median household income of $58,750 — situate the county close to national averages on several dimensions. The county's voting pattern over the last decade is most similar to that of Cibola County and Scott County.